KKR & Co. on Thursday posted first-quarter earnings that beat Wall Street expectations, and the buyout shop continued to see benefits from previous takeovers, reaching a multibillion-dollar deal to sell a company it owns.

The New York firm, alongside other private-equity owners, reached an agreement Thursday to sell orthopedic-device maker Biomet Inc. to rival Zimmer Holdings Inc. for $13.35 billion. The deal builds on a series of so-called "exits" for KKR and other private-equity firms as they seek to sell...